535 research outputs found

    Application of AI in Modeling of Real System in Chemistry

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    In recent years, discharge of synthetic dye waste from different industries leading to aquatic and environmental pollution is a serious global problem of great concern. Hence, the removal of dye prediction plays an important role in wastewater management and conservation of nature. Artificial intelligence methods are popular owing due to its ease of use and high level of accuracy. This chapter proposes a detailed review of artificial intelligence-based removal dye prediction methods particularly multiple linear regression (MLR), artificial neural networks (ANNs), and least squares-support vector machine (LS-SVM). Furthermore, this chapter will focus on ensemble prediction models (EPMs) used for removal dye prediction. EPMs improve the prediction accuracy by integrating several prediction models. The principles, advantages, disadvantages, and applications of these artificial intelligence-based methods are explained in this chapter. Furthermore, future directions of the research on artificial intelligence-based removal dye prediction methods are discussed

    Hydrogen sulfide removal from synthetic biogas using anoxic biofilm reactors

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    Tämän tutkimuksen tarkoituksena oli kehittää bioreaktoreita sulfidin poistamiseen nestemäisistä jätevirroista anoksisissa olosuhteissa. Lisäksi tavoitteena oli mahdollistaa rikkivetyä sisältävien kaasumaisten ja nitraattia sisältävien nestemäisten jätevirtojen yhtaikainen käsittely. Ensiksi tutkittiin liukoisten epäorgaanisten rikkiyhdisteiden hapetusta rikkiä hapettavia ja nitraattia pelkistäviä (SO-NR) bakteereita sisältävällä mikrobiviljelmällä kahdessa erilaisessa bioreaktorissa, leijupetireaktorissa (FBR) ja kantajakappalereaktorissa (MBBR). Bioreaktoreiden toimintaa syötteen eri typen ja rikin moolisuhteilla vertailtiin käyttäen tiosulfaattia elektronidonorina ja nitraattia elektroniakseptorina. Molemmissa reaktoreissa saavutettiin yli 98 %:n tiosulfaatin poistotehokkuus ja nitraatti saatiin poistettua kokonaan N/S-suhteen ollessa 0,5. Erittäin typpirajoitteisissa olosuhteissa (NS suhde 0,1), MBBR:llä saavutettu tiosulfaatin poistotehokkuus (37,8 %) oli korkeampi kuin FBR:llä saavutettu tiosulfaatin poistotehokkuus (26,1 %). Kun syötteen N/S suhde palautettiin arvoon 0,5, MBBR:llä tiosulfaatin poistotehokkuus palautui yhden päivän aikana arvoon 94 %, kun taas FBR:llä kesti kolme päivää, että tiosulfaatin poistotehokkuus nousi arvoon 80 %. Kummallekin reaktorille kehitettiin oman euroverkko-pohjainen malli, joka ennusti luotettavasti tiosulfaatin ja nitraatin poistotehokkuuksia eri olosuhteissa. MBBR:ään rikastunutta SO-NR-viljelmää hyödynnettiin valutusbiosuodattimessa (BTF) rikkivetyä ja nitraattia sisältävien synteettisten jätevirtojen samanaikaiseen käsittelyyn. Anoksisella BTF:llä suurin saavutettu rikkivedyn poistokapasiteetti oli 19,2 g S m-3 h-1 (99 % poistotehokkuus) rikkivetykuorman ollessa 20,0 g S m-3 h-1 (~500 ppmv) ja N/S suhteen noin 1,7. Koska nitraattia sisältävät jätevedet voivat sisältää myös orgaanisia yhdisteitä toisessa BTF:ssä tutkittiin Paracoccus versutus MAL 1HM19 kannan kykyä poistaa samanaikaisesti rikkivetyä, nitraattia ja orgaanisia yhdisteitä. Tällä BTF:llä saavutettiin nitraatin poistonopeus 16,7 g NO3--N m-3 h-1 ja asetaatin poistonopeus 42,0 g-asetaattia m-3 h-1. Saavutetut poistonopeudet olivat korkeampia kuin autotrofisia SO-NR bakteereja hyödyntävällä BTF:llä saavutetut arvot, jotka olivat 11,1 g NO3--N m-3 h-1 ja 10,2 g-asetaattia m-3 h-1. SO-NR bakteerien hallitseman anoksisen BTF:n toimintaa tutkittiin vaihtuvissa olosuhteissa kuten muuttuva kaasun ja valutusnesteen virtausnopeus, katkonainen nitraatin syöttö ja rikkivedyn shokkikuormitus, sillä tällaiset häiriöt ovat mahdollisia käytännön sovelluksissa. Olosuhteiden ohimenevät muutokset vaikuttivat merkittävästi rikkivedyn poistokapasiteettiin. Esimerkiksi rikkivedyn shokkikuormituksen jälkeen kesti 1,7 päivää ennen kuin rikkivedyn poistotehokkuus palasi yli 99 %:n tasolle. Yhteenvetona voidaan todeta, että MBBR mahdollisti tehokkaamman tiosulfaatin poiston kuin FBR erityisesti typpirajoitteisissa olosuhteissa. MBBR:n ja BTF:n osoitettiin palautuvan nopeasti ohimenevistä kuormitustilanteista ja mahdollistavan siis vakaan epäorgaanisten rikkiyhteisen poiston synteettisistä jätevirroista.The aim of this work was to develop and study anoxic bioreactors for the removal of reduced inorganic sulfur compounds from liquid and gaseous waste streams. In addition, the aim was to enable process integration for the simultaneous treatment of H2S con-taminated gas streams and NO3--containing wastewater. The experiments related to sulfide oxidation in the liquid phase were conducted in two different attached growth bioreactors, i.e. a fluidized-bed reactor (FBR) and a moving bed biofilm reactor (MBBR), inoculated with the same mixed culture of sulfur-oxidizing nitrate-reducing (SO-NR) bacteria. The bioreactors were operated under different nitro-gen-to-sulfur (N/S) molar ratios using S2O32- and NO3- as an energy source and electron acceptor, respectively. Results revealed that both the FBR and MBBR achieved S2O32- removal efficiencies (RE) >98% and completely removed NO3- at an N/S ratio of 0.5. Under severe nitrate limitation (N/S ratio of 0.1), the S2O32- RE in the MBBR (37.8%) was higher than that observed in the FBR (26.1%). In addition, the MBBR showed better resilience to nitrate limitation than the FBR as the S2O32- RE was recovered to 94% within 1 day after restoring the feed N/S ratio to 0.5, while it took 3 days to obtain 80% S2O32- RE in the FBR. Artificial neural network models were successfully used to predict the FBR and MBBR performance, i.e. S2O32- and NO3- RE as well as sulfate production. The SO-NR biomass from the MBBR was used to inoculate an anoxic biotrickling filter (BTF), which was studied for simultaneous treatment of H2S and NO3- containing waste streams. In the anoxic BTF, a maximum H2S elimination capacity (EC) of 19.2 g S m-3 h-1 (99% RE) was obtained at an inlet H2S load of 20.0 g S m-3 h-1 (~500 ppmv) and an N/S ratio of ~1.7. As some NO3--containing wastewaters can also contain organic compounds, the anoxic BTF inoculated with Paracoccus versutus strain MAL 1HM19 was studied for the simultaneous treatment of H2S, NO3- and organic carbon containing waste streams. With this BTF, NO3- and acetate removal rates of 16.7 g NO3--N m-3 h-1 and 42.0 g acetate m-3 h-1, respectively, were achieved, which was higher than the values observed in the BTF inoculated with the mixed culture of autotrophic SO-NR bacteria (11.1 g NO3--N m-3 h-1 and 10.2 g acetate m-3 h-1). Anoxic BTFs were operated under several transient conditions (i.e. varied gas and trickling liquid flow rates, intermittent NO3- supply and H2S shock loads) to evaluate the impacts of sudden changes that usually occur in practical applications. The different transient conditions significantly affected the H2S EC of the anoxic BTF. After applying H2S shock loads, the H2S RE fully recovered to >99% within 1.7 days after resuming normal operation. In summary, the MBBR was more effective for the removal of S2O32- than the FBR, es-pecially under nitrate limited conditions. Based on the short recovery times after expo-sure to transient-state conditions, the anoxic MBBR and BTF were found to be resilient and robust systems for removal of reduced sulfur compounds under autotrophic and mixotrophic conditions

    Municipal wastewater treatment with pond technology : historical review and future outlook

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    Facing an unprecedented population growth, it is difficult to overstress the assets for wastewater treatment of waste stabilization ponds (WSPs), i.e. high removal efficiency, simplicity, and low cost, which have been recognized by numerous scientists and operators. However, stricter discharge standards, changes in wastewater compounds, high emissions of greenhouse gases, and elevated land prices have led to their replacements in many places. This review aims at delivering a comprehensive overview of the historical development and current state of WSPs, and providing further insights to deal with their limitations in the future. The 21st century is witnessing changes in the way of approaching conventional problems in pond technology, in which WSPs should no longer be considered as a low treatment technology. Advanced models and technologies have been integrated for better design, control, and management. The roles of algae, which have been crucial as solar-powered aeration, will continue being a key solution. Yet, the separation of suspended algae to avoid deterioration of the effluent remains a major challenge in WSPs while in the case of high algal rate pond, further research is needed to maximize algal growth yield, select proper strains, and optimize harvesting methods to put algal biomass production in practice. Significant gaps need to be filled in understanding mechanisms of greenhouse gas emission, climate change mitigation, pond ecosystem services, and the fate and toxicity of emerging contaminants. From these insights, adaptation strategies are developed to deal with new opportunities and future challenges

    Monitoring biological wastewater treatment processes: Recent advances in spectroscopy applications

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    Biological processes based on aerobic and anaerobic technologies have been continuously developed to wastewater treatment and are currently routinely employed to reduce the contaminants discharge levels in the environment. However, most methodologies commonly applied for monitoring key parameters are labor intensive, time-consuming and just provide a snapshot of the process. Thus, spectroscopy applications in biological processes are, nowadays, considered a rapid and effective alternative technology for real-time monitoring though still lacking implementation in full-scale plants. In this review, the application of spectroscopic techniques to aerobic and anaerobic systems is addressed focusing on UV--Vis, infrared, and fluorescence spectroscopy. Furthermore, chemometric techniques, valuable tools to extract the relevant data, are also referred. To that effect, a detailed analysis is performed for aerobic and anaerobic systems to summarize the findings that have been obtained since 2000. Future prospects for the application of spectroscopic techniques in biological wastewater treatment processes are further discussed.The authors thank the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors also acknowledge the financial support to Daniela P. Mesquita and Cristina Quintelas through the postdoctoral Grants (SFRH/BPD/82558/2011 and SFRH/BPD/101338/2014) provided by FCT - Portugal.info:eu-repo/semantics/publishedVersio

    Biosorption of methylene blue dye using seaweed biomass

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    Azo dye has been extensively used in textile dyeing processes due to its simplicity in production, cost effectiveness, ease of application, durability, and availability in various colours.. At present, investigation on treatment system that promoting environmental and economic sustainability for the remove dyes from industries have received numerous attentions among researchers. Therefore, this study is aimed to investigate the potential of Malaysian seaweed to be used as a biosorbent for the removal of azo-dye, methylene blue (MB) in aqueous solutions. The screening of five indigenous species was based on their maximum biosorption capacity (qmax) and affinity (b) and the effect of pre-treatment. Characterisation of potential seaweed was determined by fourier transform infrared spectrophotometer (FT-IR), Scanning electron microscopy with energy dispersive X-Ray analysis (SEM-EDX), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and points zero charge (pHpzc). The effect of various operational parameters such as contact time (5–360 min), pH (2–11), biosorbent dosage (0.2–1.2 g/L), initial concentration (50–200 mg/L) and temperature (30–50C) on biosorption was investigated further using batch mode study under One-factor-at-time (OFAT) approach. Upon optimisation, the experimental design for the biosorption process was carried out via Response Surface Methodology-Central Composite Design (RSM-CCD). A total of 20 runs were carried out to generate a quadratic model. A desorption study was performed to investigate the reusability of E.spinosum. Non-linear models of equilibrium isotherm (consisting of two-parameter models and three-parameter models) and kinetic isotherm were applied to analyse the biosorption mechanism. Model verification using Artificial Neural Networks (ANN) was adopted for an accurate prediction of dye removal. The results reveal that the equilibrium time for all seaweed species can be achieved within 60–80 min at 27°C. At lower MB initial concentrations ( 95%) is obtained at the equilibrium time of 60 min, pH solution of 6.9–7.1, dosage of 0.72 g/L, and initial dye concentration of 300 g/L. Experimental data complied with the following equilibrium isotherms: Toth > Sips = Hill = Brouers-Sotolongo > Freundlich> Redlich-Peterson > Koble-Corrigan > Langmuir > Temkin, Dubidin-Radushkevich. The kinetic data, however, were better fitted to the pseudo-second-order kinetic model. After four consecutive biosorption/desorption cycles, the MB dye biosorption efficiency decreased from 94.5% to 48.5%, and the dye desorption efficiency decreased from 51.5% to 23.4%. Finally, model verification using ANN demonstrated that the ANN model (R2 = 0.9994, adj-R2 = 0.9916, MSE = 0.19, RMSE = 0.4391, MAPE = 0.087, and AARE = 0.001) is able to provide an accurate prediction. As a conclusion, red seaweed of E.spinosum was found to have great potential as an alternative natural occurring biosorbent specifically for MB dye removal

    Pathways to Water Sector Decarbonization, Carbon Capture and Utilization

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    The water sector is in the middle of a paradigm shift from focusing on treatment and meeting discharge permit limits to integrated operation that also enables a circular water economy via water reuse, resource recovery, and system level planning and operation. While the sector has gone through different stages of such revolution, from improving energy efficiency to recovering renewable energy and resources, when it comes to the next step of achieving carbon neutrality or negative emission, it falls behind other infrastructure sectors such as energy and transportation. The water sector carries tremendous potential to decarbonize, from technological advancements, to operational optimization, to policy and behavioural changes. This book aims to fill an important gap for different stakeholders to gain knowledge and skills in this area and equip the water community to further decarbonize the industry and build a carbon-free society and economy. The book goes beyond technology overviews, rather it aims to provide a system level blueprint for decarbonization. It can be a reference book and textbook for graduate students, researchers, practitioners, consultants and policy makers, and it will provide practical guidance for stakeholders to analyse and implement decarbonization measures in their professions

    Pathways to Water Sector Decarbonization, Carbon Capture and Utilization

    Get PDF
    The water sector is in the middle of a paradigm shift from focusing on treatment and meeting discharge permit limits to integrated operation that also enables a circular water economy via water reuse, resource recovery, and system level planning and operation. While the sector has gone through different stages of such revolution, from improving energy efficiency to recovering renewable energy and resources, when it comes to the next step of achieving carbon neutrality or negative emission, it falls behind other infrastructure sectors such as energy and transportation. The water sector carries tremendous potential to decarbonize, from technological advancements, to operational optimization, to policy and behavioural changes. This book aims to fill an important gap for different stakeholders to gain knowledge and skills in this area and equip the water community to further decarbonize the industry and build a carbon-free society and economy. The book goes beyond technology overviews, rather it aims to provide a system level blueprint for decarbonization. It can be a reference book and textbook for graduate students, researchers, practitioners, consultants and policy makers, and it will provide practical guidance for stakeholders to analyse and implement decarbonization measures in their professions

    Textile dye wastewater characteristics and constituents of synthetic effluents : a critical review

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    Textile industries are responsible for one of the major environmental pollution problems in the world, because they release undesirable dye effluents. Textile wastewater contains dyes mixed with various contaminants at a variety of ranges. Therefore, environmental legislation commonly obligates textile factories to treat these effluents before discharge into the receiving watercourses. The treatment efficiency of any pilot-scale study can be examined by feeding the system either with real textile effluents or with artificial wastewater having characteristics, which match typical textile factory discharges. This paper presents a critical review of the currently available literature regarding typical and real characteristics of the textile effluents, and also constituents including chemicals used for preparing simulated textile wastewater containing dye, as well as the treatments applied for treating the prepared effluents. This review collects the scattered information relating to artificial textile wastewater constituents and organises it to help researchers who are required to prepare synthetic wastewater. These ingredients are also evaluated based on the typical characteristics of textile wastewater, and special constituents to simulate these characteristics are recommended. The processes carried out during textile manufacturing and the chemicals corresponding to each process are also discussed
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